Generate Driving licence number

dl.py

#! /usr/bin/python3

# Thing for making up a valid (ish) driving licence number
# https://www.drivercheck.co.uk/find-out-more/photocard-driving-licence-explained/
# Note checksum is just dumped on there, not generated cos IDK how it's calculated

import argparse
from datetime import date
from typing import Tuple


def parse_date(date_str: str) -> date:
    try:
        return date.fromisoformat(date_str)
    except ValueError:
        raise argparse.ArgumentTypeError("Invalid date format. Please use YYYY-MM-DD.")


def parse_name(name_str: str) -> Tuple[str, str, str | None]:
    match name_str.split(" "):
        case (str(first_name), str(last_name)):
            return first_name.upper(), last_name.upper(), None

        case (str(first_name), str(middle_name), str(last_name)):
            return first_name.upper(), last_name.upper(), middle_name.upper()

        case _:
            raise argparse.ArgumentTypeError(
                'Invalid name. Please use "first_name middle_name last name."'
            )


def main():
    parser = argparse.ArgumentParser(description="Driving licence number generator")
    parser.add_argument("date", type=parse_date, help="Date in the format YYYY-MM-DD")
    parser.add_argument("name", type=parse_name, help="Firstname Lastname")
    parser.add_argument(
        "-g",
        "--gender",
        choices=["f", "m", "🤷‍♂️"],
        default="🤷‍♂️",
        required=False,
    )
    args = parser.parse_args()

    parts = []

    first_name, last_name, middle_name = args.name

    # Driver number (5): Driving licence number format explained.
    # JONES – Displaying the first five letters of your surname. If a surname is less than five characters in length, the remaining spaces will comprise of the digit 9.
    parts.append(last_name[:5].ljust(5, "9"))
    # 849339 – First and last numbers are the year of birth.
    parts.append(args.date.strftime("%Y")[2])
    # The second and third numbers are the month of birth.
    # (Note: in the case of female driving licence holders, ‘5’ is added to the second digit, this means that the second digit will be 5 or 6).
    if args.gender == "f":
        parts.append(str(int(args.date.strftime("%m")) + 50))
    else:
        parts.append(args.date.strftime("%m"))
    # The fourth and fifth digits are the day of the month of your birth.
    parts.append(args.date.strftime("%d"))
    # Last number of year
    parts.append(args.date.strftime("%Y")[3])
    # TS – The first two initials of your forenames.
    parts.append(first_name[:1])
    # If you have only one initial then the second character will be a ‘9’.
    parts.append(middle_name[:1] or "9")
    # 9AD – Computer check digits.
    parts.append("9AD")

    print("".join(parts))


if __name__ == "__main__":
    main()